From publisher blurb:
The Plains of Dorack are generally controlled by the evil mage Faltor the Demented who resides in his magically created fortress. The Onyx Spire rises in the middle of the Great Plains and the land around it has been cleared for miles so that its owner can keep an eye on his domain. He employs a large number of humanoids as well as humans, and rules out of fear and intimidation. While the powerful mage does not need it personally he finds that having so many minions allows him time for personal research. Those who have met the secretive mage know immediately they are in the presence of great evil.
This adventure setting was designed for 1st/2nd Edition AD&D for the Filbar Campaign for a mid-level adventurer group and DM. This adventure is easily adaptable to most any game and system. Save yourself some time and utilize it for a one shot adventure or a continuing campaign!